The present invention relates to dynamoelectric machines and, more particularly, to a stator lamination and stator cooling arrangement for such machines.
Dynamoelectric machines such as rotary electric motors are generally provided with some form of cooling in order to extend the operating capability of the machines. In general, it is desirable to maintain the temperature of such machines below a predetermined limit in order to prevent deterioration of the machine through thermal breakdown of insulation or thermal distortion due to thermal expansion of elements of the machine. In air cooled dynamoelectric machines, air is forced through air passages in the stator core as well as along surfaces of the rotor and adjacent windings in the machine. The air may be forced by external means but is generally drawn in through apertures or vents in the end bell or caps by a fan coupled in driving relationship with a rotating assembly and rotor of the machine. Air passages are formed in the stator core for passage of this cooling air so as to carry heat from the machine. In general, the stator core air passages are formed as round or oval passages adjacent the outer periphery of the stator core.
As increased horsepower has been demanded from such dynamoelectric machines while the physical size has been maintained or, in some instances, reduced, there has been a concurrent requirement to provide more efficient cooling of the machines. Such demand and requirement have necessitated development of improved cooling without impacting electromagnetic design of such machines.